tl;dnr: What it says in the title. Likewise, this theory also explores the possibility that Leta Lestrange - a character introduced in Fantastic Beasts by passing mention - may, in fact, be Snape's grandmother, and Eileen Prince's mother. It is possible that Leta herself was a "natural Legilimens" - something her family, the Lestranges, may have been known for - and, in turn, her (possible) daughter and grandson inherited this ability as well.

This would explain why Snape is such a talented / gifted Legilimens and Occlumens, even being able to fare in his own right against Lord Voldemort.

As some abilities - namely, being a Metamorphmagus (Tonks and Teddy) and being a Parselmouth (the Gaunts) - are shown and stated in the series to be inherited abilities, it's quite possible that Legilimency / Occlumency could be yet another addition to that list.

In the Harry Potter books, one of the main focal points of the series is the character Severus Snape, and how he is "one of the wizarding world's most powerful Legilimens", after Voldemort himself. Likewise, Snape was also gifted naturally at Occlumency, so much so that he could be very well considered "the wizarding world's most gifted Occlumens".

According to the HP Wiki:

Snape's unerring ability to conceal his thoughts and feelings from external penetration proved to be crucial for him. For seventeen years, he managed to hide facts from Lord Voldemort such as his remorse for Lily Evans's death and his secret alliance with Albus Dumbledore; it was his mastery of hiding his mind that made both sides distrust him.

Snape was also skilled at Legilimency; Harry Potter often felt as if Snape had the ability to read minds even before learning what the art was. Snape used Legilimency on Harry constantly while attempting to teach him Occlumency in their private lessons. Since Voldemort was considered history's greatest legilimens and was unable to ever read Snape's mind, despite being in the same room with him on many occasions, Snape could be history's greatest occlumens.

Considering how Voldemort would have detected Snape resisting penetration, Snape likely used a different branch of occlumency to allow Voldemort to read what were actually faux thoughts with the latter being none-the-wiser. In addition, Snape may have been such a good actor, Voldemort may simply have never felt a reason to use legilimency against him. (Source)

It should be noted that, even within the Harry Potter series, aside from Dumbledore and Voldemort, no other character even comes close to the level of mastery and talent that Snape seems to have for both Legilimency and Occlumency. We don't even see someone who can match Snape's skill in the Wizarding World as a whole...until, of course, Fantastic Beasts was released.

In Fantastic Beasts, we see the introduction with very powerful, "naturally gifted" Legilimens with Queenie Goldstein, the American witch. Queenie is such a powerful - and yet completely untrained - Legilimens that she has no filter, and can read the minds of almost everyone she sees / meets instantly.

From the HP Wiki:

Queenie was an extremely accomplished Legilimens who could relatively easily look deep down into the story of someone if she really wanted to, which could sometimes be a lot for her to take on; however, an Occlumens of immense power, like Gellert Grindelwald, was able to fully conceal his true thoughts from her, as Queenie was unable to see through his Percival Graves disguise. Unlike Severus Snape, who needed to train his skills, Queenie was said to have a natural talent. (Source)

The citation for the last line came from J.K. Rowling's Twitter:

"Snape had to train a slight natural ability. Queenie was born with a great talent, though she's not infallible." (Source)

However, even in spite of Rowling's Twitter response - given how press releases for the Fantastic Beasts sequels are starting to increasingly tie-in the new franchise to the original Harry Potter series - I still think there is a definite possibility that Snape didn't just happen to have a "slight natural ability" that he happened to train. If that were the case, I believe we would be seeing a lot more Legilimens and Occlumens on Snape's level in the books - and that simply isn't what we see.

So, if Snape's prodigy-level mastery of both Legilimency and Occlumency aren't merely from training alone, that leaves another, likely option: he inherited his abilities, most likely from his mother, Eileen Prince.

Given how Snape is described as "similar" to his mother in the books, I would not be surprised if Eileen Prince herself, like Queenie Goldstein, was one of these "natural Legilimens" - and that her son, Severus Snape, is such a powerful Legilimens himself because he inherited [at least some of] his mother's ability.

In the film, it's also almost strange how Newt Scamander seems to recognize Queenie's ability immediately, even though Legilimency is supposed to be rare in the wizarding world. This means that, somehow, Newt became familiar with the concept - perhaps, then, due to his connection with the Slytherin Pureblood girl Leta Lestrange.

If we are to go a step further, perhaps Leta Lestrange - the Slytherin girl that Newt Scamander once knew so well - was a "natural Legilimens" herself. [This would also explain why Newt recognized Queenie as one so quickly.]

This is especially true, given that Legilimency is not taught at Hogwarts. So, how did Newt learn about it, and how to recognize when another person is a Legilimens...unless, of course, he once knew one?

As per the HP Wiki:

Like Occlumency, Legilimency is not regularly taught at Hogwarts School of Witchcraft and Wizardry. Considering that it invades peoples' privacy, Legilimency may be a legally restricted magical practise, just as the use of Veritaserum is strictly regulated by the Ministry of Magic. (Source)

If this is the case, then Leta Lestrange could possibly even, given the timelines, be Eileen Prince's mother - and, thus, Snape's maternal grandmother. This would mean that Snape inherited some of his natural ability for Legilimency (and, in turn, Occlumency) from his mother, and in turn, his grandmother.

It may also explain how, and why, the Lestrange family was valued so highly by Lord Voldemort - if they were known for having a "Dark" reputation due to their "family gift" for Legilimency, given Voldemort was one of the world's most talented Legilimens in his own right, he would definitely value the Lestranges as followers.

This is especially true as Bellatrix Lestrange, though a Lestrange by marriage as opposed to birth, instructed Draco Malfoy in Occlumency.

As per the HP Wiki:

Bellatrix Lestrange may have been a Legilimens as she is known to have trained Draco Malfoy in Occlumency; presumably she had to be able to penetrate his mind with Legilimency in order to teach him how to repel such an attack. However, it is also possible that she simply coached him on repelling mental assault whilst having someone else attempt Legilimency on him during practise. (Source)

Many have speculated that the name "Lestrange" itself comes from the French phrase l'étrange, literally "the strange one", referring to Bellatrix's mental disturbance. However, it could, in fact, come from the same etymological (language) base as "Legilimens" - which is probably derived from the Latin legere, "to read", and mens, "mind".

If you place Latin legere - "to read" - with the Latin word extraneus - "external, strange, that which is on the outside" (forerunner of estrange) - you literally get "LeExtrange / LeStrange" - or, in bastardized Latin, "to read that which is on the outside". Sounds like Legilimency, no?

Queenie also says of the Lestrange family, "Isn't that family a little...you know...[Dark]?", in a scene directly relating to her reading Newt's mind. Newt reacts poorly to this, telling Queenie to "stay out of his head / mind", while appearing hurt and upset over his memories of Leta Lestrange.

Snape himself even says to Harry Potter of Legilimency, and how it is generally regarded as "Dark":

Harry Potter: "You mean if he knows about it, then he'll be able to read my mind?"

Severus Snape: "Read it, control it, unhinge it. In the past it was often the Dark Lord's pleasure to invade the minds of his victims, creating visions designed to torture them into madness. Only after extracting the last exquisite ounce of agony, only when he had them literally begging for death would he finally... kill them."

As for more evidence that Severus Snape shares Queenie Goldstein's talent for Legilimency, Snape - like Voldemort and Dumbledore - doesn't have to use the Legilimens spell to enter someone else's mind. Only the "most gifted of Legilimens" are able to do this, indicating that Snape is, in fact, far more gifted than Rowling claims.

"Snape gave Harry a swift, piercing look. Harry looked at the floor...Could Snape possibly know they'd found out about the Philosopher's Stone? Harry didn't see how he could — yet he sometimes had the horrible feeling that Snape could read minds....This wasn't the first time Snape had given Harry the impression of being able to read minds...Snape was looking right at him... 'He knew it was me, I could tell.'" (Sorcerer's / Philosopher's Stone / Chamber of Secrets)

"Snape's eyes were boring into Harry's. It was exactly like trying to stare down a hippogriff. Harry tried not to blink... 'Malfoy is not having hallucinations... if your head was in Hogsmeade, so was the rest of you.'...Harry bit his lip. He didn't know what had happened and didn't want to admit it — but Snape seemed to have guessed the truth." (Prisoner of Azkaban)

Last, but not least, I wanted to touch upon Snape's blood status and personality, especially as it related to Eileen Prince, his mother, and Leta Lestrange, his possible grandmother. As the Lestrange family is regarded as one of the "Sacred Twenty-Eight" Pureblood families of wizarding Britain, and Eileen Prince is generally regarded as a Pureblood herself, Leta would work as Eileen's prospective mother.

This is especially true if Leta eventually marries a male of the Prince family, as is tradition, especially amongst the predominantly Slytherin Pureblood families. After all, we see the Lestranges side with Voldemort, and Bellatrix Lestrange's fanatical, blood purist views, indicating that the Lestrange family, like the Blacks, also supported "blood purity" and "Pureblood supremacy". This would also be why the family later sided with Lord Voldemort.

From what we know of Leta Lestrange, she also shares some similarities with Severus Snape. Namely, Leta's relationship with Newt Scamander almost directly mirrored that of Severus Snape and Lily Evans.

Queenie: "That was a real close friendship you had at school."

Newt: "Yes, well, neither of us really fitted in at school, so we-"

Queenie: "-became real close. For years."

Just as Severus Snape and Lily Evans bonded over being outsiders, so, too, did Leta Lestrange and Newt Scamander. Likewise, Leta also conducted dangerous experiments during her time at Hogwarts, and shared a "love of reading", and, presumably, brilliance, with Severus Snape.

From the HP Wiki:

In 1913, one of Leta's experiments involving a Jarvey went wrong, endangering the life of another student. Rather than see his good friend expelled, Newt took the blame and was sentenced to be expelled from Hogwarts in her place. (Source)

Leta was also described as a "quite complicated, damaged and confused lady". As per her actress, Zoe Kravitz:

"The relationship between Leta and Newt Scamander is a complex relationship, so I think there will be a lot of time for that to grow and develop, which will be fun." (Source)

If there is one other character that the words "quite complicated" and "damaged" have also been used to describe in the series, it's Severus Snape.

J.K. Rowling also stated:

"Snape is all grey. You can't make him a saint: he was vindictive & bullying. You can't make him a devil: he died to save the wizarding world." (Source)

And Pottermore says of Snape:

"Severus Snape is a complicated man who could be seen in both a good and a bad light. He could be caustic, he could be mean, but he could also be scarily on point." (Source)

And, as per Queenie Goldstein calling Leta Lestrange a "taker", so, too, could this word be used to describe Severus Snape in many regards. Namely, Snape had a major character flaw of selfishness, which even Dumbledore, at times, felt "disgusted" by.

While we don't know much about Snape's mother, Eileen Prince, I think it's safe to reason that some of Snape's personality likely comes from his mother. In turn, it is likely that Eileen - if Leta was her mother - inherited traits from Leta that she later passed to her son, Severus. Hence, the similarities we see with Leta's and Snape's characters thus far.

As a final note, it should also be stated here that, currently, from what we know of Fantastic Beasts 2, Leta Lestrange will also play a "larger role" in that film. If the original film is set in 1926 - and Eileen Prince was born in 1929, as per the HP Wiki - then the timelines almost match up there.

(For reference, the sequel is currently planned for 1928 - the year before Eileen's birth.) (Source)

As we will see Leta and Newt's relationship "explored" in the sequel film(s) (Source), it could be that Newt and Leta will meet again - but, this time, Leta chooses tradition and someone else (according to this theory, the male Prince) over Newt. She is bethrothed to / marries the male Prince, getting pregnant with Eileen. Newt is devastated that the woman he loved chose another man.

This, in turn, later causes Newt's romance with Tina Goldstein to further blossom, later leading to them marrying, as per Rowling.

As the film's sequel is currently set to take place partly in the UK, and partly in Paris (Source) - the latter known as "the City of Love" - this would also be a fitting story to explore.

I find this to be an interesting fan theory, so I'd love to know if it actually is true. The idea that Newt and Leta were super close outcasts in school makes me kinda happy, and I'd love to read a fic on that.

Rowling said Snape had to "train a slight natural ability". This doesn't speak of great talent. He was moderately skilled in it but Voldemort was the one who was an expert. Snape's gift was in Occlumency, and he ultimately proved more talented in Occlumency then Voldemort was in legilimency. The theory would make more sense if Eileen was also naturally gifted in Occlumency and shut herself off emotionally. It could also explain why she was so distant with her son at King's Cross in the memories.

It doesn't speak of great passive talent, but would allow great trained active talent. It would seem that Snape did have the capability to infer a number of things without use of the spell, but he did use a powerful form of it, via spell use, against Harry when training Harry to close his mind.

Rowling said Snape had to "train a slight natural ability". This doesn't speak of great talent.

As I pointed out, while Rowling says one thing, the books she wrote clearly say another.

While I was reading the books, I noticed that literally no other characters are mentioned as being as good as Voldemort, Dumbledore, and Snape at Legilimency. It could be just Harry's POV, but even then, I feel like we would've seen more characters be capable Legilimens in the books if "training a slight natural ability" was all it took to be one.

However, the books gave me the opposite impression. For example, the would-be "obvious" cases, the Aurors, who are supposed to be "highly trained and skilled", have absolutely zero mention of being trained in Occlumency or Legilimency - something you think would be part of their standard training, but...I guess not. Mad-Eye and Tonks, both professional Aurors, are never mentioned as being skilled in Legilimency - something you think Rowling would at least mention offhand, given her "training" quote.

(May-Eye may have trained himself, but most of his ability seems down to his magical, enchanted eye.)

This is why I doubt what Rowling says on Twitter, because it's inconsistent with her own, previous work.

Personally, I take lack of evidence is evidence of lack. While it is not conclusive proof, in any system of prepoderance of the evidence, lack of evidence for, counts as evidence against. Therefore, it is reasonable to assume, given the lack of evidence for advanced training in certain skills that seem somewhat genetic (i.e. Parseltongue, bodily Transfiguration, etc.), and the plethora of evidence for inheriting magical skills, that "training" alone cannot account of Snape's mastery of Occlumency, as well as of Legilimency.

Especially true since we know that Harry himself - who later became Head Auror, if you count Cursed Child as canon - had a huge struggle and a lot of trouble even trying to learn Occlumency from Snape. He just did not seem suited at all to the field(s). Yet Harry, even as an Auror, is never mentioned as having further Occlumency / Legilimency training beyond his sessions with Snape.

The theory would make more sense if Eileen was also naturally gifted in Occlumency and shut herself off emotionally.

It is certainly possible that Eileen was naturally gifted in Occlumency, as Occlumency and Legilimency seem closely related to each other. However, a "natural Occlumens" would probably be a lot harder to notice or detect than a "natural Legilimens".

It says that snape may very well be considered one of the greatest legilemens there is. however just a couple months practice with lestrange, draco seems to able to block him out.so i disagree with that point.

Snape is a bad teacher. He is great at what he does, but he is bad at teaching. His teaching method for Harry's Occlumency was a quick overview of theory and then to hit him with the spells that revealed Harry's deepest thoughts.

That's the equivialent of Michael Phelps telling a kid to move their arms and feet then throwing them in the deep end.

And Harry is a pretty poor student, too. There's an element of truth to what Snape tells Bellatrix and Narcissa at the beginning of Half Blood Prince: ".He's mediocre in the extreme, and survives with the help of more talented friends" (ie Hermione)

Harry isn't necessarily a bad student. What he wants, more than anything, is to be normal. As such, he bristles under Snape's continual humiliation and provocation.

Look at his O.W.L. results. He got a D in History of Magic because he passed out halfway through the exam. He got a P in Divination. And that's it. He passed every other O.W.L. In fact, outside of an A in Astronomy, he got E or O in every other subject he studied. Including Potions.

Hermione absolutely helped Harry with his homework, but there was nothing she could do to help him during his O.W.L.s and he still did quite well.

In fact, Snape thinks so little of Harry's ability that he makes literally no effort to teach him anything. Ever. In any of the books. Most of his Potions lessons are either dry lectures or 'open your books to page 394 and make this potion' and then he walks around and mocks students who can't do that which they haven't been shown how. His 'teaching' of Occlumency to Harry is to berate him about how much he hated his dad, then tell him to keep his emotions in check, and then to hit him with a spell. Why is it a surprise that if you hammer on the biggest emotional trigger that a teenager has and then ask them to control their emotions, that they wouldn't be able to? Only a sociopath would do that to someone and then berate them for their failure.

Snape was a brave man. He was instrumental in seeing Voldemort killed for good. But the man bore a grudge like few others can and failed to see the potential that (literally) everyone else saw in Harry simply because Harry's father was a dick to Snape when they were kids. In fact, I have a headcannon scene that occurs after Voldemort's exposure at the ministry where Dumbledore absolutely tears Snape a new asshole because he let a grudge from 20 years ago get in the way of even trying to teach Harry effectively.

Think about it! Harry's talent for D.A.D.A. (which Snape maligned) kept him alive, when, had Snape actually swallowed his pride for two seconds, considered the greater good, and taught Harry Occlumency, Harry wouldn't have even been at the Ministry in the first place.

I'm thinking that you can learn Legilimancy(sp?) through use of a spell and have different levels of power that way. You can also be born with the natural talent with varying levels. Snape was born lower mid-range with his natural gift, but extremely powerful with the spell. There would have been consequences to Snape's mission to use the spell on malfoy. Malfoy was accomplished enough with Occlumency to fend off Snape's inherent ability, but wouldn't have been a match for Snape's spell. Malfoy would've known though and reported it back to the other deatheaters that already didn't trust Snape.

I think the simplest explanation for this is that Snape was taking it easy on Draco. After all, look at the lengths Snape went to help care for and protect Draco, as opposed to how Snape treated Harry. Snape even made the Unbreakable Vow (which kills you if you break it) to kill Dumbledore in case Draco couldn't do it.

While the latter was part of Dumbledore's plan anyways, Snape always treated Draco a lot more leniently than he did Harry in the books. Likewise, I don't find it unreasonable at all that Snape probably went easier on Draco than he did with Harry, and perhaps even helped give Draco better training / more patience and time to learn.

I think the simplest explanation for this is that Snape was taking it easy on Draco.

Or that he is simply unable to do so. I would be very pleased to know why you're so convinced of his greatness in that field when the author clearly tells you that you're wrong and the books seems to go that way too. Harry being an open book for anyone having some competences in legilimency isn't a proof of wonderful skills.